Effective [3+1+1+1] Cycloaddition to Six‐Membered Carbocycle Based on DMSO as Dual Carbon Synthon

Abstract A [3+1+1+1] cycloaddition was developed among 2‐arylpropene, ketone and DMSO in the presence of K 2 S 2 O 8 . 2‐arylpropene provides three carbons, ketone offers one carbon, and DMSO as dual carbon donor contributes two carbons to the six‐membered carbocycle. It gave the cyclohexene motif and spirocyclohexene skeleton. Four C−C bonds formed in this process. Both propylene and ketone could be well tolerated and give the corresponding cyclohexene or spirocyclohexene motif in useful yields. Based on the controlled experiments, a possible mechanism was proposed. magnified image